To the best of my knowledge, only 7 survivors committed suicide--none directly related to their Titanic experience. There are claims that Dodge was murdered and Frauenthal accidentally fell, but I think the evidence weighs in for suicide--especially in the case of Dr. Dodge.
1. Dr. Washington Dodge--1919--gunshot wound to the head due to business and investment problems.
2. Dr. Henry William Frauenthal--1927--jumped from his apartment balcony after months of depression partially resulting from the mental illness of his wife.
3. Johan (John) Niskanen--1927--gunshot wound to head and burns after he set his cabin on fire--depression over failure to strike gold on his property in California.
4. Jack Thayer--1945--throat slit with razor due to depression over the loss of his son, Edward Cassatt Thayer, during World War II.
5. John Morgan Davis--1951--ingested poison during the Christmas holidays after his wife left him.
6. Phyllis May Quick--1954--gunshot wound to the head allegedly due to marital problems.
7. Frederick Fleet--1965--hung himself on a clothesline--due to depression following the death of his wife Eva and being evicted from his home by her brother.
There is also a possibility that
gambler George Brayton committed suicide by throwing himself in front of a train in Calexico, California in 1920. I haven't been able to prove that that George Brayton is the same man on Titanic.
Madeleine Astor's cause of death was more likely an accidental overdose of prescription drugs.